A compressor, a device for sucking fluid and increasing pressure, is widely used for an air-conditioner, refrigerator, or the like. There are many kinds of compressors according to a driving method, including a reciprocating compressor, a scroll compressor and a turbo compressor, etc.
The compressor consists of a compression mechanism unit for performing compression of the fluid and a driving unit for driving the compression mechanism unit. The driving unit commonly uses a motor converting electric energy to kinetic energy.
An overload protecting apparatus for sensing heat generated from a rotor and a stator is installed near the motor. If an overheat is generated, the overload protecting apparatus stops driving of the motor so that the motor may not be damaged from the overload.
However, as for the overheating of the compressor, generally, the motor may be overloaded, and in addition, if the temperature of the discharged fluid is too high due to an abnormal operation, carbonization of oil, damage of parts and an unstable operation would cause degradation of a reliability of the compressor.